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Trial registered on ANZCTR


Trial ID
ACTRN12607000106437
Ethics application status
Approved
Date submitted
8/12/2006
Date registered
6/02/2007
Type of registration
Retrospectively registered

Titles & IDs
Public title
Can macadamia nuts be part of a weight loss diet?
Scientific title
The effects of long-term ingestion of macadamia nuts on weight control in overweight subjects
Universal Trial Number (UTN)
Trial acronym
M.E.D.O.W. (Macadamia Enriched Diets for OverWeight subjects)
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Obesity 1600 0
Condition category
Condition code
Diet and nutrition 1703 1703 0 0
Obesity

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
A description of the study: Once recruited, subjects will be randomly assigned to either a test pre-entry diet or control group. The test pre-entry ‘loading’ group will have their usual (baseline) diet assessed to determine their overall energy intake and percentage contribution of energy nutrients as well as fatty acid (FA) composition. Based on the percentage of their dietary fat intake, Macadamia nut and oil products will be provided to substitute a major proportion (~20%) of the usual source of dietary fat without affecting total daily energy intake, i.e. isocaloric with usual baseline diet. This pre-entry ‘loading’ phase will continue for a period of 10 weeks, after which time subjects from each of the test pre-entry ‘loading’ diet and control groups will be randomly assigned to one of two different energy-controlled weight reduction diets.

In the energy-controlled (second) phase of the trial, the test diet will consist of moderately high fat intake (35-40%) with a large proportion (~20%) derived from macadamia nuts. Each diet will be progressively adjusted to facilitate a reduction in body weight of 0.5-1.0 kg per week.

The test period will endure 6 months duration in the first instance, with subjects being monitored regularly over a period of up to 18 months. This protocol will involve regular face-to-face consultations over this time to enable collection of samples and present opportunities to sustain adherence to the dietary protocol. Specifically visits at 0, 1, and 4 weeks, followed by two-monthly visits during the weight loss protocol will be conducted for subject monitoring. Additional consultation will be provided as required for each subject. Dietary data in the form of 3-day food records, 24 hour dietary recall and food frequency questionnaires will be taken to monitor adherence.

Non-invasive anthropometric measures (BMI, waist and hip circumference, bioelectrical impedance) and endothelial function tests will be conducted as well. Blood samples will be taken both to screen for subject eligibility and to provide information on risk factors such as serum lipids, markers of inflammation and to cross-validate dietary data. A proportion of samples will be allocated to low temperature storage to enable retrospective biochemical analysis.

Pre-Entry Intervention Group: Usual diet modified to allow for pre-determined amount of macadamia nuts.

Weight Loss (energy-controlled) Phase Intervention Group: a moderately high fat (close to 35% of energy) monounsaturated fat-enriched, energy-controlled, weight loss diet including a pre-determined amount of macadamia nuts daily.
Intervention code [1] 1492 0
Prevention
Comparator / control treatment
Pre-Entry Control Group: Usual diet. In the energy-controlled (second) phase of the trial, The control diet will be a moderately low fat diet (20-25%) aligned with the American Heart Association (AHA) Step II Diet. Diet will be progressively adjusted to facilitate a reduction in body weight of 0.5-1.0 kg per week.
Control group
Active

Outcomes
Primary outcome [1] 2364 0
Weight loss
Timepoint [1] 2364 0
Primary outcome [2] 2365 0
Amelioration of Cardiovascular risk profile, which will be assessed by tracking a range of demonstrated pre-disposing factors including:
- Body weight in relation to body mass index
Timepoint [2] 2365 0
Measured at baseline, 10 weeks, 14 weeks, monthly for 6 months of weight loss trial, then two-monthly until trial exit.
Primary outcome [3] 2366 0
Amelioration of Cardiovascular risk profile, which will be assessed by tracking a range of demonstrated pre-disposing factors including:
- Body Composition in relation to Body Mass Index
Timepoint [3] 2366 0
Mmeasured at baseline, 10 weeks, 14 weeks, monthly for 6 months of weight loss trial, then two-monthly until trial exit
Primary outcome [4] 2367 0
Amelioration of Cardiovascular risk profile, which will be assessed by tracking a range of demonstrated pre-disposing factors including:
- Body composition using waist-hip ratio and bio-electrical impedance as routine measures
Timepoint [4] 2367 0
Measured at baseline, 10 weeks, 14 weeks, monthly for 6 months of weight loss trial, then two-monthly until trial exit
Primary outcome [5] 2368 0
Amelioration of Cardiovascular risk profile, which will be assessed by tracking a range of demonstrated pre-disposing factors including:
- Biochemical risk factors for atherosclerosis: serum triglycerides, total cholesterol, high density lipoprotein cholesterol (HDL) and low density lipoprotein cholesterol (LDL)
Timepoint [5] 2368 0
Measured at baseline, at 10 weeks, 6 months and at trial exit
Primary outcome [6] 2369 0
Amelioration of Cardiovascular risk profile, which will be assessed by tracking a range of demonstrated pre-disposing factors including:
- Biochemical risk factors for Myocardial Infarction: inflammatory predisposition (C-reactive protein)
Timepoint [6] 2369 0
Measured at baseline, 10 weeks, 6 months, and at trial exit
Primary outcome [7] 2370 0
Amelioration of Cardiovascular risk profile, which will be assessed by tracking a range of demonstrated pre-disposing factors including:
- Physiological risk factor for Myocardial Infarction: endothelial function measured via flow-mediated brachial artery vasodilation
Timepoint [7] 2370 0
Measured at baseline, 10 weeks, 6 months, and at trial exit
Primary outcome [8] 2371 0
Amelioration of Cardiovascular risk profile, which will be assessed by tracking a range of demonstrated pre-disposing factors including:
- Behavioural risk factors: dietary intake and physical activity
Timepoint [8] 2371 0
Measured at baseline, monthly for 9 months, then every 2nd month
Secondary outcome [1] 4119 0
Anthropometric measures (body weight, waist-hip ratio).
Timepoint [1] 4119 0
Measured at baseline, 10 weeks, 14 weeks, monthly for 6 months of weight loss trial, then two-monthly until trial exit.
Secondary outcome [2] 4120 0
High Density Lipoprotein (HDL) & Low Density Lipoprotein (LDL) cholesterol, total cholesterol, triglycerides, inflammation markers.
Timepoint [2] 4120 0
All measured at baseline, at 10 weeks, 6 months and at trial exit.
Secondary outcome [3] 4121 0
Body composition (bioelectrical impedance)
Timepoint [3] 4121 0
Measured at baseline, 10 weeks, 14 weeks, monthly for 6 months of weight loss trial, then two-monthly until trial exit.
Secondary outcome [4] 4122 0
Brachial artery vasodilation
Timepoint [4] 4122 0
Measured at baseline, 10 weeks, 6 months, and at trial exit.

Eligibility
Key inclusion criteria
BMI 27-50 kg/m2; waist circumference F= >88 cm, M= >102 cm; non-smoker >1 year; blood pressure systole >100 and <140 mmHg, diastole <90mmHg; total fasting cholesterol less than 260mg/dl; total fasting triglycerides less than 400 mg/dl; total fasting glucose less than 126 mg/dl; normal liver and kidney function; willing to modify diet and other health behaviours; not planning to become pregnant or move during the study; have no food allergies to nut products; subjects must not be currently following any particular diet and must not have intentionally lost weight by dieting during the previous 3 months; subjects must not be taking nutritional supplements other than a daily multivitamin (or be willing to stop taking nutritional supplements if needed); subjects must be willing to maintain current physical activity routine, which cannot exceed the equivalent of >30 minutes per day or moderate-intensity activity; Blood hematocrit normal; subjects must be willing to comply with all study-related procedures; not using medication (insulin or oral) to control blood sugar.
Minimum age
26 Years
Maximum age
55 Years
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Any medical condition that may make weight loss medically inadvisable; history of kidney failure or disease; cancer diagnosis within 2 years prior to study entry; consumption of more than 3 alcoholic drinks a day; type I or type II diabetes; current use of hypolipidemics, anti-psychotics; hypoglycaemics, glucocorticoids or thyroid medication; plan to move during the study; current participation in another clinical trial; pregnancy or breast-feeding; liver disease; high cholesterol; diabetes; HIV positive; Syphilis; Hepatitis B/C positive; does not meet age requirement; habitual smoker; food allergies; unwillingness to provide written consent; personal history of cardiovascular disease, including prior myocardial infarction, angioplasty, or bypass surgery; known cardiovascular or metabolic disease; currently using medications to control blood pressure, lipids or glucose; currently on diet or attempted weight loss by dieting in last 3 months; currently exercising more than the equivalent of 30 minutes/day or moderate intensity physical activity; currently on oral contraceptives; history of alcohol or drug abuse; known allergy or sensitivity to nuts; known atherosclerotic cardiovascular disease; history of congestive heart failure; history of non skin malignancy in previous 5 years or skin malignancy in previous 2 years; any major active rheumatologic, pulmonary, hepatic, renal, dermatologic disease or inflammatory condition; history of HIV positive; weight loss inducing medications or dietary supplements within 3 months prior to enrolment; weight loss > 5kg in last 6 months; serious or unstable medical or psychological conditions that, in the opinion of the investigator, would compromise the subject’s safety or successful participation in the study.

Study design
Purpose of the study
Prevention
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Sealed envelopes are held by an independent person, and opened by the independent person to assign the intervention group.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Computer-generated random numbers (Excel), in blocks at entry, subjects are randomised twice: to pre-entry and weight loss phases of study
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Type of endpoint(s)
Efficacy

Recruitment
Recruitment status
Recruiting
Anticipated date of first participant enrolment
8/12/2006
Actual date of first participant enrolment
Anticipated date last participant enrolled
Actual date last participant enrolled
Anticipated date of last data collection
Actual date of last data collection
Target sample size
60
Actual sample size
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 1849 0
Charities/Societies/Foundations
Name [1] 1849 0
Horticulture Australia
Address [1] 1849 0
Country [1] 1849 0
Australia
Primary sponsor type
University
Name
Griffith University
Address
Country
Australia
Secondary sponsor category [1] 1664 0
University
Name [1] 1664 0
University of Queensland
Address [1] 1664 0
Country [1] 1664 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 3448 0
Griffith University
Ethics committee address [1] 3448 0
Ethics committee country [1] 3448 0
Australia
Date submitted for ethics approval [1] 3448 0
Approval date [1] 3448 0
07/11/2005
Ethics approval number [1] 3448 0
PBH/09/05/HREC

Summary
Brief summary
This study will determine if macadamia nuts are an appropriate food to include in diets to address weight loss and other factors associated with coronary heart disease.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 27426 0
Address 27426 0
Country 27426 0
Phone 27426 0
Fax 27426 0
Email 27426 0
Contact person for public queries
Name 10681 0
Dr. Shawn Somerset
Address 10681 0
School of Public Health
Griffith University
University Drive
Meadowbrook QLD 4131
Country 10681 0
Australia
Phone 10681 0
+61 7 33821027
Fax 10681 0
+61 7 33821034
Email 10681 0
s.somerset@griffith.edu.au
Contact person for scientific queries
Name 1609 0
Dr. Shawn Somerset
Address 1609 0
School of Public Health
Griffith University
University Drive,
Meadowbrook. 4131
Country 1609 0
Australia
Phone 1609 0
+61 7 33821027
Fax 1609 0
+61 7 33821034
Email 1609 0
s.somerset@griffith.edu.au